One- and two-photon scattering from generalized V-type atoms

TL;DR

This paper derives an analytical two-photon scattering matrix for a generalized V-type atom in a waveguide, revealing how two-photon scattering can distinguish atomic level structures and exhibit phenomena like two-photon transparency.

Contribution

It provides the first analytical form of the two-photon scattering matrix for N-level V-type atoms in a waveguide, highlighting the ability to differentiate atomic structures via two-photon processes.

Findings

Two-photon scattering matrix distinguishes different atomic level structures.

Destructive interference leads to two-photon Coupled-Resonator-Induced Transparency.

Nonlinear two-photon scattering vanishes under single-photon transparency conditions.

Abstract

The one- and two-photon scattering matrix S is obtained analytically for a one-dimensional waveguide and a point-like scatterer with N excited levels (generalized V -type atom). We argue that the two-photon scattering matrix contains sufficient information to distinguish between different level structures which are equivalent for single-photon scattering, such as a V -atom with N = 2 excited levels and two two-level systems. In particular, we show that the scattering with the V -type atom exhibits a destructive interference effect leading to two-photon Coupled-Resonator-Induced Transparency, where the nonlinear part of the two-photon scattering matrix vanishes when each incident photon fulfills a single-photon condition for transparency.